Instances are useful for duplicating geometry by referencing an original copy to save memory and time when processing and rendering many objects. These instances can then be shaded differently to create interesting and realistic variations without overloading the artist or the computer with many unique copies.

Copy to Points SOP

Create a Copy to Points SOP and wire geometry to be instanced into the first input, and positions to instance to in the second input. 

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Instance OBJ

Create an Instance OBJ

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as you would normally create Houdini instances. 

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In the Instance node, set your Instance object and select Fast point instancing.  This will emit RenderMan ObjectInstance.  Note that if you select Full point instancing or Off for Point instancing, it will not create instances but copies of the object instead.

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or Full point instancing. Currently these two options result in the same behavior in the renderer.

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To override material for the instanced objects, we can use the Material SOP inside the Instance.

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Here is an example hip file that shows how to override Bxdf and color variation using the Material SOP.